| 摘要 |
A metal halide lamp according to the present invention includes a discharge tube ( 3 ) having an envelope ( 18 ) that is formed of a translucent ceramic and has a main tube portion ( 16 ), a first slender tube portion ( 17 a) and a second slender tube portion ( 17 b) respectively formed in both end portions of this main tube portion ( 16 ), and a first electrode lead-in member ( 21 ) and a second electrode lead-in member ( 22 ) having a first electrode portion ( 25 a) and a second electrode portion ( 25 b) formed in their respective tip portions. The individual electrode lead-in members ( 21, 22 ) are inserted in the respective slender tube portions ( 17 a , 17 b), and a gap ( 23 ) is formed respectively between the slender tube portion ( 17 a , 17 b) and the electrode lead-in member ( 21, 22 ). A proximity conductor ( 19 ) is provided on an outer surface of the discharge tube ( 3 ), at least 2 turns of part of the proximity conductor ( 19 ) are wound helically around an end portion of the first slender tube portion ( 17 a) on a side of the main tube portion ( 16 ). The proximity conductor ( 19 ) is connected electrically to the second electrode portion ( 25 b). An amount of sealed mercury in the discharge tube ( 3 ) is equal to or smaller than 2.5 mg/cm<SUP>3</SUP>. The restarting characteristics are improved considerably.
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